In 2012, there were 8.2 million cancer deaths and 14.1 million new cases of cancer worldwide (Ferlay et al., GLOBOCAN 2012 v1.0, Cancer Incidence and Mortality Worldwide: IARC CancerBase No. 11 [Internet]. Lyon, France: International Agency for Research on Cancer; 2013; available at globocan.iarc.fr). These values are projected to increase to an estimated 22.2 million new cases and 13.2 million deaths by 2030 (Ferlay et al., Lancet Oncol 13:790-801, 2012). While new treatment techniques are being explored, the use of chemotherapeutic drugs, including platinum- (Pt-) based drugs has remained mainstream (see, e.g., Harper et al., Chem Eur J 16:7064-7077, 2010; Casini and Reedijk, Chem Sci 3:3135-3144, 2012; Wexselblatt and Gibson, J Inorg Biochem 117:220-229, 2012; and Florea and Büsselberg, Cancers 3:1351-1371, 2011). Only a few platinum drugs have been approved for clinical use, however. These include cisplatin, carboplatin, and oxaliplatin, which are Pt(II) complexes approved for use worldwide, as well as lobaplatin, nedaplatin, and heptaplatin, which are approved for use in China, Japan, and Korea, respectively (Harper et al., supra; Casini and Reedijk, supra; Wexselblatt and Gibson, supra; Florea and Büsselberg, supra; and Wang and Guo, Chem Soc Rev 42:202-224, 2013).
Despite being commonly prescribed, the clinical application of platinum drugs continues to be limited by a narrow spectrum of activity, resistance, and toxic side effects. Accordingly, there remains a need for platinum-based drugs having improved efficacy and reduced toxicity.